<template>
  <div>
    <div>
      <ul>
        <li v-for="(item, index) in bookArr" :key="index">
          {{ item.name }} <button @click="addFn(index)">买书</button>
        </li>
      </ul>
    </div>
    <table>
      <tr border="2" width="500" cellspacing="0">
        <th>序号</th>
        <th>书名</th>
        <th>单价</th>
        <th>数量</th>
        <th>合计</th>
      </tr>
      <tr v-for="(item,index) in bookArr" :key="index" >
        <td>{{index+1}}</td>
        <td>{{item.name}}</td>
        <td>{{item.price}}</td>
        <td>{{item.count}}</td>
        <td>{{item.price*item.count}}</td>
      </tr>
    </table>
    <p>总价格为:{{counts}}</p>
  </div>
</template>

<script>
export default {
  data() {
    return {
      counts: 0,
      bookArr: [
        {
          name: "水浒传",
          price: 107,
          count: 0,
        },
        {
          name: "西游记",
          price: 192,
          count: 0,
        },
        {
          name: "三国演义",
          price: 219,
          count: 0,
        },
        {
          name: "红楼梦",
          price: 178,
          count: 0,
        },
      ],
    }
  },
  methods: {
    addFn(index) {
      console.log(1);
      this.bookArr[index].count += 1
     this.counts = this.bookArr . reduce( (sum ,item )=> sum += item.price*item.count ,0)
    }
  }
}
</script>

<style lang="scss" scoped></style>
